LF: Simple ATO

[piusma]

Setting up a temp. quarantine tank and just needing a simple ATO. Please let me know if you have one for a good price. Thank you.
Steven

[mike31154]

If looks are not that important, then a simple gravity feed ATO would be easy to set up with parts you may already have. All you need is a container fitted with a spout or valve at the bottom, some tubing (flex and rigid air line) and a mechanical float valve (furnace humidifier float valve works well).

I have a similar set up although it's not gravity feed since the ATO container I use is a bit large to set up above my display, so it's beside it instead. I use a small air pump on a digital timer to pressurize the container. The air pressure pushes the water out of the container into the display through the aforementioned mechanical float valve. For this you need a container that can be made air tight with a stopper which needs to have two holes, one for a short tube (air in) and a long tube (water out). Other than that, I have a small check valve between the air pump and the container to guard against possible back flow. I also had to DIY a bracket to hold the mechanical float valve. Pics follow.

Glass wine carboy (about 7 US gals)



Float valve

[viperfish]

Doesn't get much simpler than that. Do you have any froblems with salt interfering with the float, mainly the seal. I had thought about doing something like this but I was afraid at some point the thing wouldn't seal and cause an overflow.

[Seamazter]

You do always keep less water in your fill pail then what will overflow your system.
If you set it up correctly then even if it does get stuck open your system will not overflow if they full pail gets dumped in.
make your top off water just enough to not overflow your system and you should be good.
The sticking float valve wont be a problem.

[mike31154]

Originally Posted by medhatreefguy

Doesn't get much simpler than that. Do you have any froblems with salt interfering with the float, mainly the seal. I had thought about doing something like this but I was afraid at some point the thing wouldn't seal and cause an overflow.

No problems so far and it's been running for a good 6 months or more. The inlet is well above the water and since it's RODI water running through there, I don't really anticipate it plugging up any time soon. Besides, the consequences of it plugging solid are not necessarily critical if you catch it within a day or two. Just means your system is not getting topped off and the air pump will only be able to put a given amount of pressure into the carboy, insufficient I suspect to pop the plug out. Even then, so what. Occasionally I throw some DOW flake calcium chloride into the top off water and that hasn't caused any plugging issue either.

Edit: Just realized you're talking about the valve not sealing as opposed to getting plugged up. Again, not an issue so far, see comments below in answer to Seamazter's concern regarding overflowing issues. These humidifier float valves are pretty bullet proof, after all, they run trouble free on furnace humidifiers for years, some with very hard water flowing through them. One of the advantages of this type of top off is that even when the valve is fully open, it's a very low pressure trickle going in, so everything happens rather slowly, which is a good thing.

Seamazter, good point about limiting the fill amount, but I'm currently running sumpless, so I'm taking a bit of a chance with the overfilling issue. Before I added the float valve, I used to simply run the input water through a plastic air regulator valve, so I had to be mindful of the timer settings to run the air pump because the plastic air regulator had no shut off. Several times I had the pump timer on manual and forgot about it. One time I was out of the house when I forgot and came back home just as the display was starting to spill over! Lucky. Wasn't long after that, that I installed the float valve as extra insurance. I think the air regulator did kind of limit the input flow once the tubing became submerged and added some additional backpressure against the input flow. Probably what saved my butt from a larger flood. With the level I have the float valve currently set at, if something goes wrong the tank may be able to handle a gallon and a half before spilling over, so if the carboy is full, that'll be six gallons on the floor. It would take a while to get there though, since the timer limits the on time of the pump and I don't need to bump up the level by going manual anymore, I've got the timings cased now.

[piusma]

I might try something similar, I'm trying to run a ATO for a quarantine tank for only 4-6 weeks. Thanks for the idea.
Steven